Integrated system and process for heat treating castings and reclaiming sand

Abstract

Provided is a five-in-one process/integrated furnace system that (i) receives and heat treats a casting, (ii) removes sand core materials from the casting, (iii) actively reclaims sand from the sand core materials, (iv) substantially cools the reclaimed sand, and (v) removes fines from the reclaimed sand. The furnace system includes a heating chamber disposed above and contiguous with a cooling chamber. The heating chamber and cooling chamber are preferably constructed so that heat and gasses pass therebetween. The heating chamber is preferably in the general form of a heat treating furnace. The heating chamber receives and heat treats metal castings. During the heat treating process, sand core materials are dislodged from the castings and enter into a sand reclaiming region. A hot fluidized bed functions to reclaim sand from the sand core materials within the heating chamber. The sand reclaimed in the hot fluidized bed falls into a cool fluidized bed in the cooling chamber which is preferably directly beneath the heating chamber. Gasses are drawn from above the cool fluidized bed in a manner that removes fines and heat from the reclaimed sand. The fines are separated from the heated gasses, which are used in the hot fluidized bed.

I claim: 
     
       1. A method for processing a casting having a sand core and reclaiming sand from the sand core, the sand core comprising sand particles bound together by a binder material, the sand core defining a cavity within the casting, and the method comprising steps of: receiving the casting, with at least a portion of the sand core therein, in an elongated heating chamber within a furnace system;   heating the heating chamber to a temperature sufficient to loosen a portion of the sand core, whereby portions of the sand core are loosened from the cavity and exit the casting while the casting is within the furnace system;   moving the casting along a path through the elongated heating chamber, whereby portions of sand core exit the casting at a plurality of varing locations alone the path of the moving casting;   collecting portions of sand core at a plurality of locations along the path of the casting; and   promoting migration of the collected portions of sand core through the heating chamber alone a path parallel to the path of the moving castings toward and over a weir to discharge sand from the heating chamber.   
     
     
       2. The method of claim 1, wherein the promoting step includes the step of promoting migration of the collected sand portions in the same direction as the direction of movement of the casting along their path. 
     
     
       3. The method of claim 1, further comprising the step of reclaiming sand, wherein the reclaiming step includes a step of fluidizing within the heating chamber the portions of the sand core that exit the casting, wherein the fluidizing step includes the step of further heating binder material of the fallen portions of the sand core; and   wherein said promoting step includes, at least, the step of promoting migration of the collected portions of sand core in a fluidized bed.   
     
     
       4. The method of claim 3, further comprising the steps of: discharging the reclaimed sand from the fluidized bed and the heating chamber directly into a cooling chamber.   
     
     
       5. The method of claim 4, further comprising the steps of: cooling the reclaimed sand, wherein the cooling step includes a step of fluidizing the sand within the cooling chamber so that gases are pre-heated within the cooling chamber; and   collecting the pre-heated gases from the cooling chamber and utilizing the pre-heated gases in the reclaiming step.   
     
     
       6. The method of claim 3, further comprising steps of: drawing gases from the furnace system, and   extracting fines from the sand by entraining fines in the gases drawn from the furnace system.   
     
     
       7. The method of claim 3, wherein the heating step further comprises the step of heating the heating chamber to a temperature sufficient to heat treat the casting. 
     
     
       8. The method of claim 3, wherein the heating step further comprises the step of heating the heating chamber to a temperature sufficient to combust a combustible binder material acting as the binder material of the sand core. 
     
     
       9. The method of claim 3, further comprising the step of heat treating the casting within the furnace system. 
     
     
       10. The method of claim 9, wherein the heat treating step is accomplished in an upper area of the heating system and the loosened sand core material falls from the casting to a lower area of the furnace system, and the reclaiming step includes the step of fluidizing core material in the lower area. 
     
     
       11. The method of claim 6, wherein the reclaiming step further includes a step of fluidizing portions of the sand core with the gases of the drawing step. 
     
     
       12. The method of claim 4, further comprising the step of fluidizing the sand in a cool fluidized bed in the cooling chamber. 
     
     
       13. The method of claim 12, further comprising the step of: drawing gases from proximate to the cool fluidized bed to capture waste heat from proximate to the cool fluidized bed, and   wherein the reclaiming step further includes a step of fluidizing the portions of the sand core in the heating chamber with the gases of the drawing step.   
     
     
       14. The method of claim 13, further comprising a step of separating the fines from the gases prior to the step of fluidizing the sand core in the heating chamber.